This invention relates generally to the testing of electrical integrated circuits, and more particularly the invention relates to sockets for receiving packaged integrated circuits for test purposes.
The packaged integrated circuit typically includes a polymer or ceramic housing for a semiconductor chip with electrical leads extending from the package which are electrically connected to the semiconductor chip. In a dual in-line package (DIP), the electrical leads are arranged in two parallel rows with the leads depending from the bottom of the housing.
Packaged integrated circuits must undergo a number of different tests, each test requiring the insertion of the integrated circuit package and leads into a test socket. To prevent bending or damage to the leads, zero insertion force (ZIF) sockets have been devised to limit the force exerted on the leads when the package is inserted into a test socket. The most widely known and used ZIF sockets are from 3M Corporation and Aries Corporation. In these sockets the leads of a DIP (dual in-line package) are pinched between two pieces of metal which are, in turn, soldered to a printed circuit board. The metal pieces are held in place by the body of the ZIF socket which is typically made of plastic. The metal pieces are electrically conducting to provide a good electrical path from the DIP lead to the printed circuit board in which the ZIF socket is attached. In all cases, the bodies of these sockets are made of some organic material (plastics or polymers) which can only withstand temperatures as high as 250.degree. C. for extended periods of time. The metal used to pinch the leads of the IC DIP packages are beryllium copper alloy or beryllium nickel alloy for a high temperature operation not to exceed 250.degree. C. While these sockets perform well within their stated specifications, they cannot be used at temperatures in excess of 250.degree. C. because the materials will decompose and fail.
The present invention is directed to providing a test socket which is simple in design and reliable in high temperature (above 250.degree. C.) environments.